[IAUC] CBET 1131: 20071111 : SUPERNOVA 2007on IN NGC 1404

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                                                  Electronic Telegram No. 1131
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2007on IN NGC 1404
     N. Morrell, G. Folatelli, and M. Stritzinger, on behalf of the Carnegie
Supernova Project, report that a spectrogram (range 375-912 nm) of 2007on
(cf. CBET 1121), obtained on Nov. 11.29 UT with the du Pont 2.5-m telescope
(+ WFCCD) at Las Campanas Observatory, shows this to be a type-Ia supernova a
few days before maximum light.  Adopting the NED recession velocity of 1947
km/s for the host galaxy (from Graham et al. 1998, A.Ap. Suppl. 133, 325),
the 'superfit' spectrum-comparison code (Howell et al. 2005, Ap.J. 634, 1190)
provides the best match to SN 2004gs at three days before maximum.  The
spectrum shows the characteristics of relatively fast-declining supernovae,
similar to those of SN 1986G, with strong Si II 597.2-nm absorption relative
to Si II 635.5-nm.  A strong P-Cyg line identified as O I 777.3-nm is
observed.  Considering the recession velocity given above, the maximum
absorption of the Si II 635.5-nm line indicates an expansion velocity
of about 12000 km/s.


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                         (C) Copyright 2007 CBAT
2007 November 11                 (CBET 1131)              Daniel W. E. Green